The present invention relates generally to a syringe and capsule therefore, and more specifically to a dental placement syringe and disposable capsule for use therewith.
Dental syringes and disposable plastic capsules for dispensing dental material are well known in the art. Disposable capsules, such as those described in U.S. Pat. Nos. 4,969,816; 5,165,890; 5,172,807; 5,306,147; and 5,336,088, are available in a number of sizes and shapes for dispensing a variety of dental materials. They essentially comprise a plastic body having an internal reservoir, a large diameter opening on one end and a small diameter discharge tip on the opposite end, as well as a separate piston or plug inserted into the large opening.
The internal reservoir is filled with dental material, and the plug seals the material within the reservoir. As the plug is pushed deeper into the reservoir, dental material is dispensed from the discharge tip. The capsules may be preloaded with dental material, or may be loaded on site as needed.
Dental syringes, such as those described in U.S. Pat. Nos. 5,061,179; 5,306,147; and 5,336,088, hold the disposable capsules in place, and have a longitudinally moving plunger that can push the plug into the reservoir, dispensing the dental material in a controlled fashion.
The longitudinally moving plunger is typically moved by squeezing or compressing a spring loaded handle or plunger. A full compression of the handle results in all the dental material being dispensed.
Although dental syringes and disposable capsules have become a convenient way to dispense a controlled amount of dental material into a patient's mouth, the size and shape of existing syringes can cause inconvenience. Syringes that are thin and fit easily into a patient's mouth, such as described in U.S. Pat. No. 5,129,825, must be held like a conventional manually operated syringe, using two fingers and the thumb to hold the device, with the thumb depressing the plunger. Positioning the hand with the thumb and fingers spread is uncomfortable and can quickly become tiresome. Holding the syringe by its rear portions also creates difficulty in controlling the exact location of the capsule tip and placement of the dental material.
Pistol grip syringes, such as described in U.S. Pat. No. 5,061,179, are more comfortable for the dentist's hand and can allow more precise placement of the dental material, but are bulky and difficult to fit in the small confines of an oral cavity.
Another difficulty in using conventional syringes is that once the dental material is dispensed, it cannot be drawn back into the reservoir. If too much material has been dispensed, the dentist must use another tool to pick up the excess. This is because the syringe's longitudinally moving plunger can only push the plug deeper into the reservoir. After an amount of material is dispensed, releasing the handle will allow the handle and longitudinally moving aperture to return to their original positions, but the plug will be left in the farthest forward position inside the capsule tip.
For the foregoing reasons, there is a need for a device that will allow a dentist to precisely dispense, and possibly recollect, a controlled amount of dental material into a patient's mouth in a manner that is comfortable for both the dentist and the patient.